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\chapter*{Preface}

This thesis was prepared at the Department of Mathematics, the Technical University of Denmark in partial fulfillment of the requirements for acquiring the Master of Science degree in Computer Science and Engineering.

The thesis is based on the implementation and evaluation of tradeoff attacks on the HiTag2 stream cipher. Three important tradeoff parameters are considered including the time taken for the attack, memory required for precomputation and the length of output available from the stream cipher. The thesis presents cryptanalysis results for four different tradeoff attacks by varying these parameters for each attack. 

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Lyngby, September 2008\\
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Rajesh Bachani
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